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The game stars an unnamed marine, a survivor of Bravo Team from the original Doom 3. He awakens after the ambush on his squad and is soon confronted by Dr. Garret, who presents him Sam, a flying droid capable of opening doors and hacking computers. Together with Sam, the survivor makes his way through the Mars facility, battling zombies and demons on his way through the base. His goal is to reach a port where a spaceship full of surviving members of the UAC facility is preparing to blast off. On his way, the marine meets a few survivors, collects valuable information through Sam, and visits Hell, where he closes the demon-spawning portals. Eventually, the marine is forced to leave Dr. Garret behind, and Sam sacrifices itself to prop open a closing bulkhead door on the way to the dropship. Sam manages to give the marine the data previously collected, but the game's ending implies that the UAC engages in a cover-up of the details of the invasion.

The player is taken through a total of eight linear arcade-style rail shooter stages wherein the player can tilt the device to aim and hit touch areas in the corners of the screen to fire his weapon or reload. Other touch areas on the screen appear in contextual situations similar to quick time events, allowing the player to dodge attacks or take cover from enemy fire. Gameplay typically lasts four to six hours depending on the difficulty selected from the four levels available. Performance ranks are assigned at the end of each level.

A large portion of the Doom 3 bestiary is represented. Enemies animate and attack in manners similar to their behaviors in Doom 3, though in a much more directed fashion. Enemies often appear from behind or in surprising locations near the player, as a test of reaction time.

In this game, all fat zombies have their face torn off and an opened abdomen exposing their intestines. Unlike in Doom 3, where they simply attack by swinging their fists or a weapon, these zombies will latch onto the player and try to eat him. They must be literally shaken off when this happens by moving the phone or tablet quickly back and forth.

The Z-Secs are limited to machine gun users. When one begins firing at the player, a yellow reticle will appear on screen. Once the enemy locks onto the marine's location, this reticle will turn red and damage will be taken steadily. The player can take cover before the reticle turns red in order to avoid damage, and can use this mechanic to exchange fire.

There are only two mancubi in the game, who serve as the final bosses of Hell in Abaddon. The two mancubi alternate firing projectiles from either of their arm cannons, which can be dodged if the timing so allows. It is critical to divide damage between the two mancubi evenly, as the one left alive will begin walking toward the player once one has died, and once at melee range, it will repeatedly pound the marine with its arm cannons until he rapidly dies.

The arch-vile first appears as a boss at the end of Gehenna, and then becomes a regular enemy afterward. It alternates between summoning additional low-level monsters and attacking with a psycho-kinetic wave of blue flame, which can be dodged the same as a fireball.

Hell knights are the most powerful enemy. The first fight with one occurs as a boss fight near the teleporter in Delta Labs in much the same manner as in Doom 3. Several more appear as major enemies in the following levels.

Most of the Doom 3 armory is represented in the weapons that can be found, which can be switched between using the touch area in the upper left corner. Their mechanics are similar to their Doom 3 versions, though head shots are particularly more effective and are strongly encouraged by the game. Weapons and ammunition can be found by shooting crates, referred to in-game as "secret items," and sometimes by touching loose items on the screen - occasionally this becomes an element of skill, as there will be a limited window of opportunity in which to collect an item before it is hidden or destroyed, or because it must be quickly grabbed between waves of attacking monsters.

The plasma gun behaves mostly the same as in Doom 3, but is more powerful, dispatching many enemies in only a few shots. Its plasma shots are not visible while in transit to their targets, leaving a puff of blue smoke when they impact.

The marine is given an experimental form of the BFG which fires a compact green orb of plasma. It can be charged like its Doom 3 counterpart for additional power, but it has decreased effectiveness against enemies such as the Hell knight unless a direct hit is scored - only minor enemies such as imps can be killed by its splash damage alone. The projectile does not emanate tracers.